Cutting the Risk of Tainted Platelets

By Laura Landro

Tek Image

Pooled blood platelets.

Bacterial contamination of donated platelets has become the most significant infection risk in the U.S. blood supply, as WSJ’s Informed Patient column explains today.

Donated platelets are used to help blood clot in very sick patients, such as those who have suffered severe trauma or are undergoing a bone marrow transplants. Although AABB — the large blood-bank group — in 2004 adopted new safety measures to reduce the chances that donors’ blood or skin transmits bacteria to the blood bag, a risk of contamination remains. Recent commentary in the journal Transfusion warned that bacterial contamination of platelets remains a major cause of sepsis and death, despite the implementation of testing.

“Although the overall risk is relatively low compared with other medical procedures, patients and their care providers should be aware that bacteria in the blood bag can cause severe transfusion reactions, and that more effective testing of all platelets for bacteria is an important additional step forward for blood safety,” says Matthew Kuehnert, who oversees blood safety programs for the Centers for Disease Control and Prevention.

So how can patients and families reduce the risks?

It’s important to ask what testing has been done on platelets: The freshest platelets are also likely to have the least chance of contamination, since bacteria takes time to grow. Blood banks culture blood within 24 to 36 hours of donation, but they are stored at room temperature for up to five days and small amounts of bacteria that aren’t detected have time to grow.

Patients should also ask what type of platelets they will receive. The majority of transfused platelets are so-called apheresis platelets, collected from individual donors by a process which uses a centrifuge to separate blood into its components, retain the platelets and return the blood to the donor.

But about 13% of donated platelets are separated from whole-blood donations, using a centrifuge to separate platelet-rich plasma and then concentrate platelets further. Platelets from several donors may be pooled together, which might increase the risk of contamination from several different donors’ skin bacteria.

Donors wanting to minimize the chances that they pass something along can ask about safety measures to avoid transmitting bacteria. The AABB calls for careful skin cleansing before donation, and for the first blood that is collected to be diverted into a separate bag in case skin bacteria is still present.

According to a CDC report, most blood-collection centers culture only apheresis platelets and release the unit after culture. Hospital transfusion services are responsible for bacterial testing of platelets derived from donated whole blood. Because pooling is performed immediately before transfusion, culture-based tests are logistically difficult and costly to implement for whole-blood-derived platelets, the report says.

A test from Verax Biomedical is the only rapid test approved for both apheresis and whole-blood-derived platelets to detect bacteria right before transfusion. About ten large cancer centers use it on apheresis platelets, but many Verax customers use it mainly for whole-blood derived platelets, because apheresis platelets are already tested by culture methods and secondary testing closer to the time of transfusion isn’t required by the FDA.

In a statement provided by an FDA spokeswoman, the agency says the test is valuable for detecting bacteria, but could add “significant complexity” to transfusion operations.

“Input from a public process such as a public scientific workshop and/or an external scientific advisory committee, is a warranted step before making any recommendations.”

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3:02 pm August 6, 2012

Christine Frisbee wrote :

Although we should know this information, we may not be able to protect ourselves from the exposure. Accidents happen in every medical institution. We should ask the questions when we are in the situation when we or a family member needs a transfusion. We should be aware of all of the things that can affect our health. I think this is a wonderful article and will post it on our website:http://www.TheseAreGreat.com, where we inform about health issues and great healthy products.

11:25 am August 1, 2012

John Nelson wrote :

A couple of statements in this article are really stupid. There is no way that the patient or their family should be responsible for asking that the proper testing has been done or what kind of platelets that the patient will receive. Neither customer would be able to make any sense out of the response that would be given nor should they be responsible to make decisions based on the answers. All of the responsibility rests with the organization and person giving the treatment.